AGRIS - Search

A comparative study on the nitrite and nitrate contents of 15 liver pate brands, in a total of 45 samples (three batches per brand) is presented. The study was conducted on two different kind of pates: pork liver pates and fowl liver pates. For the simultaneous determination of nitrite and nitrate, an automated flow injection system with spectrophotometric detection was used. The manifold was based on the splitting of the flow after injection and subsequent confluence of the flow before reaching the detector, allowing the reduction of nitrate to nitrite in part of the sample plug on an on-line copper cadmium reductor column. Spectrophotometric determination was made after a diazotization coupling reaction. The levels of nitrites and nitrates ranged from 1.07 mg NaNO2 kg(-1) +/- 0.43 to 15.9 mg NaNO2 kg(-1) +/- 5.2 and from 24.5 mg NaNO3 kg(-1) +/- 2.7 to 207 mg NaNO3 kg(-1) +/- 14, respectively. The levels of concentration of these constituents were below the allowable limits. A significant dispersion in the results was observed between different brands and within some of the brands.

Mostrar más [+]

other agrarian sciences agrarian sciences::other agrarian sciences ciências da saúde outras ciências agrárias health sciences ciências agrárias::outras ciências agrárias

Universidade do Porto - Portugal

Interacções fármaco-nutriente no doente com nutrição artificial

1998

Azevedo, Rute Sá Pereira Lopes Ferreira | Borges, Nuno

assunto decs (campo repetível) nutrição

Universidade do Porto - Portugal

Characterisation of 'Starking' apple polyphenoloxidase

1998

Rocha, Ada | Cano, MP | Galeazzi, MAM | Morais, AMMB | Faculdade de Ciências da Nutrição e Alimentação

Experiments were performed to optimise the extraction conditions of 'Starking' apple fruit polyphenoloxidase (PPO), to evaluate the affinity and specificity towards several substrates and to study the stability of enzyme extracts from apple samples stored under different conditions. Sodium phosphate buffer (0.2 M, pH 6.5) plus 0.25% Triton X-100 and 1% or 2% PVPP was found to be the most efficient extraction medium. Chlorogenic acid, dopamine and 4-methylcatechol showed similar specificity towards PPO, and chlorogenic acid was found to be the best substrate for the enzyme. Enzyme extracts from frozen cut apple stored at -4 degrees C, and extracts from lyophilised apple samples stored at 4 degrees C were more stable than extracts obtained from fresh-cut or acetone powder samples. (C) 1998 SCI.

Mostrar más [+]

medical and health sciences::health sciences ciências médicas e da saúde::ciências da saúde ciências da saúde health sciences

Universidade do Porto - Portugal